It's apparently not a structural design flaw, as I had feared yesterday.

For want of a functional valve.

This seems worth repeating:

For want of a nail

the shoe was lost.
For want of a shoe
the horse was lost.
For want of a horse
the rider was lost.
For want of a rider
the battle was lost.
For want of a battle
the kingdom was lost.
And all for the want
of a horseshoe nail.

Lets hope that does not come to pass.

This is the sort of thing to find out before launch (and before blowing up the launch vehicle.) I'm encouraged that Elon and his engineers are being this cautious.

Valves are the bane of liquid launch vehicles.

It really does not save any money to buy anything but the top quality valves. At Space America the 40 year old surplus Redstone valves we used worked better than the brand new commercial valves that caused us to blow the engines off the vehicle.

Dennis

For want of a valve

the tankage was lost.
For want of the tankage
the booster was lost.
For want of the booster
the payload was lost.
For want of the payload
the company was lost.
For want of a company
the cosmos was lost.
And all for the want
of a pressure relief valve.

There, I have updated it. It is a bit overstated and melodramatic but grant me a bit of artistic liscense.

Mark is right, better to have this happen on the ground than in-flight

"At Space America the 40 year old surplus Redstone valves we used worked better than the brand new commercial valves that caused us to blow the engines off the vehicle."

Dennis, are valves rated in grades base on their abilties to endure pressure and thermal stresses of is a valve a valve a valve?

Surely in this day and age, someone could make a quality part if the financial incentive were there.

So, if they had simply left it fueled while they waited for the winds to die down, they might have had a successful launch a few hours later - and would never have known about this electrical problem in the valve.

Since it was a fuel tank valve, temperature extremes shouldn't be an issue.

That's true, RP-1 is not cryogenic.

Mitch Burnside-Clapp joked that he wanted the first step in flight test to be the formal sacrifice of a LOX valve, since all rockets had one fail anyway.

Mike

It is my experience that the difference in cost and performance of valves is almost directly proportional to the amount of testing applied to them. Testing costs money and results in a more expensive part.

I have no idea what Elon's philosophy is regarding valves so claim absolutely no inside knowledge.

Valves are the bane of rockets, one way or another. The more expensive ones also have a feedback feature that would tell a computer whether or not the valve had actually worked as commanded. With the problems that they have had with valves, causing the last two problems, this might be something to integrate into their system.

-g